Volvo Center

City-Scale Transport Modeling: An Approach for Nairobi, Kenya

Daganzo, C. F.
Li, Yuwei
Gonzales, Eric J.
Geroliminis, Nikolas
2007

Traffic congestion poses problems for cities around the world, especially in rapidly growing and motorizing cities like Nairobi, Kenya. We show here how we plan to use in the context of Nairobi a new theory that relates the mobility provided by a city’s street network to the number of vehicles on the network (including private cars and public transport) and to key aggregate descriptors of both the street infrastructure and the public transport services. Conventional micro-simulation models require vast quantities of data and produce unreliable detailed results. The new theory asserts that...

Multimodal Traffic at Isolated Signalized Intersections: New Management Strategies to Increase Capacity

Xuan, Yiguang
Gayah, Vikash
Daganzo, Carlos
Cassidy, Michael
2009

New ideas are explored for managing multimodal traffic on isolated approaches to signalized intersections. Strategies are proposed that both: segregate distinct modes along the approach, and more effectively resolve the disruptive capacity-reducing conflicts that arise between through moving and turning traffic traveling in adjacent lanes. The proposed schemes produce capacities that consistently and significantly exceed those of conventional intersection treatments, and reduce travel delays for all modes. Observations at a real intersection support these claims.

Bus Lanes with Intermittent Priority: Screening Formulae and an Evaluation

Eichler, Michael
Daganzo, Carlos F.
2005

This paper evaluates strategies for operating buses on signal-controlled arterials using special lanes that are made intermittently available to general traffic. The advantage of special bus lanes, intermittent or dedicated, is that they free buses from traffic interference; the disadvantage is that they disrupt traffic. We find that intermittent lanes, unlike dedicated ones, do not significantly reduce street capacity. Intermittence, however, increases the average traffic density at which the demand is served, and as a result increases traffic delay. These delays are more than offset by...

Managing Evacuation Routes

So, Stella K.
Daganzo, Carlos F.
2009

This paper shows that evacuation routes, such as a building’s stairwell or an urban freeway, may discharge inefficiently if left unmanaged, and that setting priority rules can speed up egress. Therefore, a simple control strategy is proposed. The strategy is decentralized and adaptive, based on readily available real-time data. The strategy is shown to be optimal in two senses: (i) it finishes the evacuation in the least possible time, and (ii) it evacuates the maximum number of people at all times. In both cases, it favors the people most at risk. The results shed light on other traffic...

Urban Development on Railway-Served Land: Lessons and Opportunities for the Developing World

Cervero, Robert
2020

Under the right conditions -- serious traffic congestion, a permissive regulatory environment, and frequent and reliable transit services -- rail transit investments can powerfully shape cities and regions. Rail transit’s city‐shaping powers are due to market forces and policy interventions. By enhancing accessibility (the ability of those living, working, or shopping rail near stops to quickly reach desired destinations) rail services increase the value and desirability of properties in and around stations. Market pressures by themselves rarely produce transit oriented development. To...

Life-cycle Energy and Emissions Inventories for Motorcycles, Diesel Automobiles, School Buses, Electric Buses, Chicago Rail, and New York City Rail

Chester, Mikhail
Horvath, Arpad
2009

The development of life-cycle energy and emissions factors for passenger transportation modes is critical for understanding the total environmental costs of travel. Previous life-cycle studies have focused on the automobile given its dominating share of passenger travel and have included only few life-cycle components, typically related to the vehicle (i.e., manufacturing, maintenance, end-of-life) or fuel (i.e., extraction, refining, transport). Chester (2009) provides the first comprehensive environmental life-cycle assessment of not only vehicle and fuel components but also...

Deploying Lanes for High Occupancy Vehicles in Urban Areas

Cassidy, Michael J.
Daganzo, Carlos F.
2007

Simulations and field experiments in previous works suggest that a freeway’s general purpose lanes (those not dedicated to high occupancy vehicles) discharge vehicles from bottlenecks at an equal or higher average rate when one of the lanes is devoted to high occupancy vehicles than when it is not. This result was used in these previous works to develop formulae for the total discharge rate of bottlenecks, with and without dedicated lanes, as a function of the percentage of high occupancy vehicles in the traffic stream.This present paper extends these ideas by examining the effect of...

How to Improve Bus Service

Daganzo, Carlos F
2008

Bus schedules cannot be easily maintained on busy lines with short headways: Experience shows that buses offering this type of service usually arrive irregularly at their stops, often in bunches. Although transit agencies build slack into their schedules to alleviate this problem, their attempts often fail because practical amounts of slack cannot prevent large localized disruptions from spreading system-wide. This paper describes a more resilient control scheme that overcomes this problem. The method also produces even headways with less slack than the conventional approach. Thus, buses...

Exploring the Effect of Turning Maneuvers and Route Choice ona Simple Network

Gayah, Vikash V.
Daganzo, Carlos F.
2010

A simple symmetric network consisting of two tangent rings on which vehicles obey the Kinematic Wave Theory of traffic flow and can switch rings at the point of tangency is studied. An online adaptive simulation reveals that if there is any turning whatsoever the two-ring system becomes unevenly loaded for densities greater than the optimal density. This reduces flow. Furthermore, the two-ring system jams at significantly lower densities than the maximum density possible.

Rail + Property Development: A model of sustainable transit finance and urbanism

Cervero, Robert
Murakami, Jin
2008

Hong Kong has aggressively pursued transit value capture to finance railway infrastructure through its “Rail + Property” development program, or R+P. More than half of all revenues received by the MTR Corporation, the owner-operator of Hong Kong’s largest railway network, come from property development. A wide variety of R+P projects presently exist in Hong Kong. Most focus on housing development though all have some degree of commercial development. Recent generation R+P projects have placed a stronger premium on urban design and quality of pedestrian environments. This has generally paid...